In psychology and neuroscience, motor planning is a set of processes related to the preparation of a movement that occurs during the reaction time (the time between the presentation of a stimulus to a person and that person's initiation of a motor response). Colloquially, the term applies to any process involved in the preparation of a movement during the reaction time, including perception-related and action-related processes.

In broad definition, motor planning is referred to as any process that occurs during reaction time (RT) as a preparation of the incoming movement. This definition can include motion preparations that are not strictly motor-related. For example, the identification of a task-relevant stimulus is captured by the usual meaning of the term, "motor planning", but this identification process is not strictly motor-related.

Wong and colleagues (2015) have proposed a narrower definition to include only movement-related processes: "Specification of the movement trajectory for the desired action, a description of how the end-effector will produce such an action, and finally a description of the full set of the joint trajectories or muscle activations required to execute the movement."

Motor planning is explained by several competing and complementary theoretical models. Most commonly, motor planning in broad definition is explained to have three distinct hierarchical processes.

This process is first triggered by attention, where a person selects an object of the interest from their surrounding environment. They then apply a cognitive rule (e.g.,"reach to the red mug"), which then lead to a motor goal formation, where attention and the rules are combined to identify the desired outcomes.

Rosenbaum et al. (2004) introduced a posture-based planning model, which first identifies a best-suited limb configuration or goal posture to perform a goal task, followed by movement specification to achieve that posture. After selecting a posture, a system choose a movement trajectory to reach it.

The brain uses an internal mechanism called inverse model or forward model. Inverse model generates motor commands to achieve the desired trajectories automatically. When performing novel task, people are more likely to rely on forward model, which predict sensory outcomes from the given motor commands. Rosenbaum et al. proposed that one motion can carry multiple purposes,(e.g.,reaching the red mug while avoiding to touch the stacked glass plates), and such constraints form a hierarchy to resolve indeterminacy (elimination by aspects). Highest level constraint is the final goal ("reach the red mug") and the lower constraints include avoidance of obstacles, effort minimisation and ensuring final stability of the postures. Out of the movement options, central neural system choose the one to execute through optimal selection based on several aspects.

Motor commands generated in the second stage command the muscles to move, tailoring them according to the OFC given simultaneously. Another internal mechanism, called forward models, which predict sensory outcomes from the given motor commands, combined with inverse models, is used to give feedbacks for motion corrections.